vdr uses this ioctl to check the currently selected audio channel:
audio_status_t as;
CHECK(ioctl(fd_audio, AUDIO_GET_STATUS, &as));
return as.channel_select;
see also /usr/include/linux/dvb/audio.h:
typedef struct audio_status {
int AV_sync_state; /* sync audio and video? */
int mute_state; /* audio is muted */
audio_play_state_t play_state; /* current playback state */
audio_stream_source_t stream_source; /* current stream source */
audio_channel_select_t channel_select; /* currently selected channel */
int bypass_mode; /* pass on audio data to */
audio_mixer_t mixer_state; /* current mixer state */
} audio_status_t; /* separate decoder hardware */
The corresponding ioctl to set a new audio channel is AUDIO_CHANNEL_SELECT,
and this is supported by ivtv. But as ivtv has no AUDIO_GET_STATUS, I can`t
use the function properly with vdr.
And there is another problem:
ivtv uses a different ioctl (AUDIO_BILINGUAL_CHANNEL_SELECT) in case the
decoder receives a bilingual audio. Maybe I will have to think longer about
it, but it seems to be unnecessarily complicated.
To use the right ioctl I would need to know if the driver is in
audio_stereo_mode or audio_bilingual_mode. How can I detect this?
AUDIO_GET_STATUS has no value for it.
Or should I simply call always two different ioctls? But then again, why
does AUDIO_CHANNEL_SELECT not set both values for
CX2341X_DEC_SET_AUDIO_MODE ? My understanding is that every time an
application uses AUDIO_CHANNEL_SELECT it wants to change the current audio
channel immidiately - no matter if the stream is stereo or bilingual.
I think the driver could set the default behaviour (initial setting) without
having two different ioctls.
Greets,
Martin
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